Image forming apparatuses having specialized toner structures and materials

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority to and incorporates by reference the entire contents of Japanese Patent Application No. 2008-189144 filed in Japan on Jul. 22, 2008.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an image forming apparatus. More particularly, the present invention relates to a supporting structure for a device when the device is mounted on a top surface of a body of an image forming apparatus.

2. Description of the Related Art

Image forming apparatuses such as copying machines, facsimile machines, printers, or other printing machines are configured so that electrostatic latent images formed on latent image carriers such as photoreceptors are subjected to visible image processing with a developing agent such as toner to form visible images that are then transferred and fixed onto a recording medium such as a sheet, whereby copy output can be obtained.

Sometimes an image reading device is mounted on the upper part of a body of an image forming apparatus as disclosed, for example, in Japanese Patent Laid-open Publication No. 2006-229347.

In the conventional technique disclosed in Japanese Patent Laid-open Publication No. 2006-229347 the image reading device is mounted on a casing of the image forming apparatus. Specifically, a strut portion is mounted on both side plates of the casing. Each of the strut portions is fixed to the casing by fastening or the like. Thereafter, legs of the image reading device are loaded into a fitting portion provided in the strut portions. As a result, the image reading device is supported in a cantilever beam state.

In another conventional technique disclosed in Japanese Patent Laid-open Publication No. 2007-135243 and Japanese Patent Laid-open Publication No. 2002-23440), a mounting base for mounting an image reading device is provided on opposed peripheral portions on a rectangular plane constituting a top surface of a casing of the image forming apparatus. Moreover, an adjustment member, the height of which can be adjusted, for ensuring the flatness of the mounting surface, is provided on the mounting base.

In another conventional technique disclosed in Japanese Patent Laid-open Publication No. 2001-206558, unlike the above-mentioned conventional techniques, a dedicated mounting device is provided near an image forming apparatus to mount an image reading device. In other words, the image reading device is not mounted on a casing of the image forming apparatus.

The configuration in which the image forming apparatus is mounted on the casing of the image forming apparatus is advantageous; because, unlike the configuration disclosed in Japanese Patent Laid-open Publication No. 2001-206558, no dedicated equipment is not required.

When the casing is made by resin molding, an image reading device, which is a heavy object, cannot be directly mounted on the casing. Therefore, as disclosed in Japanese Patent Laid-open Publication No. 2006-229347, strut portions or the need to be provided to bear the weight of the image reading device.

However, in order to provide the strut portions and the like, the structure of the casing of the image forming apparatus needs to be changed. Accordingly, the act of changing the structure leads to an increase in the manufacturing costs.

Further, it should be noted that the strut portions are necessary when mounting the image reading device. Therefore, a difference in details of assembling of the body casing occurs between when the image reading device is mounted and when the image reading device is not mounted, making it impossible to render components management cost and process cost uniform regardless of whether the image reading device is mounted.

In still another convention technique disclosed in Japanese Patent Laid-open Publication No. 2006-229347, the image reading device is provided above a toner feed unit in a developing device. In this configuration, when replacing a bottle in the toner feed unit, the image reading device must be first evacuated from the mounting position. Therefore, in the image reading device, which is mounted so as to be openable and closable on the top surface of the casing, since the opening/closing supporting points are the strut portions, from the viewpoint of enhancing the rigidity, the image reading device should have a large size that can withstand a considerably high level of load. Thus, the areas occupied by the supporting portion of the image reading device on the top surface of the casing are increased, leading to a possibility of an increase in size of the structure and an increase in weight of the structure. Further, in order to prevent shifting of image forming positions caused, for example, by misregistration of the image forming device supported by the body casing, it is important that the application of load from the mounted device to the body casing as an existing structure be prevented by the strut portions.

SUMMARY OF THE INVENTION

It is an object of the present invention to at least partially solve the problems in the conventional technology.

According to an aspect of the present invention there is provided an image forming apparatus including a toner feed unit that feeds toner to a developing device in the image forming apparatus and arranged inside and near a top surface of a body casing of the image forming apparatus. The toner feed unit including a toner container configured to house therein toner; and a frame configured to hold the toner container. The frame including a toner-container storage portion having a curved concave portion to hold the toner container, the toner-container storage portion being formed of a material different from a material of the body casing; and a supporting surface that supports plural portions of a mounting target device that is configured to be mounted above the toner-container storage portion by surface contact.

According to another aspect of the present invention there is provided an image forming apparatus including a toner feed unit that feeds toner to a developing device in the image forming apparatus and arranged inside and near a top surface of a body casing of the image forming apparatus. The toner feed unit including a toner container configured to house therein toner; and a frame configured to hold the toner container. The frame including a toner-container storage portion having a curved concave portion to hold the toner container, the toner-container storage portion being formed of a material different from a material of the body casing; and a supporting surface that supports three points of a mounting target device that is configured to be mounted above the toner-container storage portion by surface contact.

According to still another aspect of the present invention there is provided an image forming apparatus including a toner feed means for feeding toner to a developing device in the image forming apparatus and arranged inside and near a top surface of a body casing of the image forming apparatus. The toner feed means including a toner container means configured to house therein toner; and a frame means configured to hold the toner container means. The frame means including a toner-container storage means having a curved concave portion to hold the toner container means, the toner-container storage means being formed of a material different from a material of the body casing; and a supporting surface means that supports plural portions of a mounting target device that is configured to be mounted above the toner-container storage means by surface contact.

The above and other objects, features, advantages and technical and industrial significance of this invention will be better understood by reading the following detailed description of presently preferred embodiments of the invention, when considered in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

<figref idrefs="DRAWINGS">FIG. 1</figref> is a schematic diagram for explaining an internal configuration of an image forming apparatus according to an embodiment of the present invention;

<figref idrefs="DRAWINGS">FIG. 2</figref> is a perspective view of a configuration of a toner feed unit used in the image forming apparatus shown in <figref idrefs="DRAWINGS">FIG. 1</figref>;

<figref idrefs="DRAWINGS">FIG. 3</figref> depicts perspective views of a configuration of principal portions of the image forming apparatus shown in <figref idrefs="DRAWINGS">FIG. 1</figref>;

<figref idrefs="DRAWINGS">FIG. 4</figref> is a perspective view of an assembled state from the dismantled state shown in <figref idrefs="DRAWINGS">FIG. 3</figref>;

<figref idrefs="DRAWINGS">FIG. 5</figref> is a partial perspective view of a part of a body casing in the configuration of the principal portion shown in <figref idrefs="DRAWINGS">FIG. 3</figref>;

<figref idrefs="DRAWINGS">FIG. 6</figref> is a diagram for explaining an assembled state between a body casing in the configuration of the principal portion shown in <figref idrefs="DRAWINGS">FIG. 3</figref> and a mounting member constituting a principal portion of a toner feed unit;

<figref idrefs="DRAWINGS">FIG. 7</figref> is a perspective view of a top surface of a mounting member in the configuration of the principal portion shown in <figref idrefs="DRAWINGS">FIG. 3</figref>;

<figref idrefs="DRAWINGS">FIG. 8</figref> is a perspective view of another configuration of a top surface of the mounting member shown in <figref idrefs="DRAWINGS">FIG. 7</figref>;

<figref idrefs="DRAWINGS">FIG. 9</figref> is a perspective view of still another configuration of a top surface of the mounting member shown in <figref idrefs="DRAWINGS">FIG. 7</figref>; and

<figref idrefs="DRAWINGS">FIG. 10</figref> is a perspective view of an outer cover of the image forming apparatus shown in <figref idrefs="DRAWINGS">FIG. 4</figref>.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Exemplary embodiments of the present invention will be explained with reference to the accompanying drawings.

<figref idrefs="DRAWINGS">FIG. 1</figref> is a schematic diagram for explaining an internal configuration of an image forming apparatus <b>1</b> according to the present invention, particularly an internal configuration including a toner feed unit provided on an upper part of a body casing. The image forming apparatus <b>1</b> is a color printer that can form a full color image by adopting a tandem system. The image forming apparatus is not necessarily limited to a color printer. In other words, the image forming apparatus can be a copying machine, a facsimile machine, or a printing machine.

In <figref idrefs="DRAWINGS">FIG. 1</figref>, an image forming apparatus <b>1</b> includes the following devices.

Specifically, devices provided in the image forming apparatus <b>1</b> include image creating devices <b>21</b>Y, <b>21</b>C, <b>21</b>M, and <b>21</b>K that form respective color images according to an original image, a transfer device <b>22</b> disposed opposite to the image creating devices <b>21</b>Y, <b>21</b>C, <b>21</b>M, and <b>21</b>K, a manual feed tray <b>23</b> and a sheet cassette <b>24</b>A mounted in a sheet feeder <b>24</b>, the manual feed tray <b>23</b> and the sheet cassette <b>24</b>A functioning as a sheet feed unit that feeds a recording sheet into a transfer region where the image creating devices <b>21</b>Y, <b>21</b>C, <b>21</b>M, and <b>21</b>K and the transfer device <b>22</b> are located opposite to each other, a pair of registration rollers <b>33</b> that feeds the recording sheet conveyed from the manual feed tray <b>23</b> or the sheet cassette <b>24</b>A in accordance with the timing of image creation by the image creating devices <b>21</b>Y, <b>21</b>C, <b>21</b>M, and <b>21</b>K, and a fixing device <b>10</b> that fixes the sheet-shaped medium subjected to transfer in the transfer region.

The fixing device <b>10</b> uses a thermal roller fixing system. The detailed explanation of the thermal roller fixing system will be omitted, but the thermal roller fixing system is a system in which an image is fixed to a recording sheet through a melting and softening step and a penetrating step by the action of heat and pressure using a heating roller and a pressure roller that are provided opposite to each other and can be abutted against each other with a recording sheet conveying path provided therebetween.

The transfer device <b>22</b> includes a belt <b>22</b>A as a transfer medium (hereinafter referred to as “transfer belt”) that is stretched around a plurality of rollers <b>22</b>A<b>1</b> and <b>22</b>A<b>2</b>. Transfer bias units <b>22</b>Y, <b>22</b>C, <b>22</b>M, and <b>22</b>K, which apply a transfer bias, are disposed at positions opposite to photoreceptor drums in the respective image creating devices. The transfer device <b>22</b> is configured so that toner images formed in the respective image creating devices are successively superimposed and transferred by applying a transfer bias having a reverse polarity to the toner.

In the transfer device <b>22</b>, a secondary transfer bias unit <b>22</b>F, which simultaneously transfers the toner images superimposed and transferred onto the transfer belt <b>22</b>A to the recording sheet, is provided on a recording sheet conveying path.

The image forming apparatus <b>1</b> can use as recording sheets any of plain papers generally used, for example, in copying, or the so-called special sheets having a larger heat capacity than sheets, for example, OHP transparency, 90 K papers such as cards and postcards, thick papers corresponding to a basis weight equal to or more than about 100 g/m², or envelopes.

The image creating devices <b>21</b>Y, <b>21</b>C, <b>21</b>M, and <b>21</b>K perform the development of a yellow color, the development of a cyan color, the development of a magenta color, and the development of a black color, respectively. The configuration of the image creating devices <b>21</b>Y, <b>21</b>C, <b>21</b>M, and <b>21</b>K is identical except the colors of the toners. Accordingly, the configuration of the image creating device <b>21</b>K will be explained as a typical example of the image creating devices <b>21</b>Y, <b>21</b>C, <b>21</b>M, and <b>21</b>K.

The image creating device <b>21</b>K includes a photoreceptor drum <b>25</b>K as an electrostatic latent image carrier, and a charging device <b>27</b>K, a developing device <b>26</b>K, and a cleaning device that are arranged in that order along the direction of rotation of the photoreceptor drum <b>25</b>K. In the image creating device <b>21</b>K, an electrostatic latent image according to image information corresponding to colors separated from each other by a writing light <b>29</b>K from a writing device <b>29</b> is formed between the charging device <b>27</b>K and the developing device <b>26</b>K. The electrostatic latent image carrier may be in the form of a drum or alternatively may be in the form of a belt. The devices for image formation, in other words, for image creation, arranged around the photoreceptor drums are housed all in a process cartridge (not shown) having a unit structure provided with a casing shown in <figref idrefs="DRAWINGS">FIG. 2</figref>.

The transfer device <b>22</b> is extended obliquely. Accordingly, the space necessary for the transfer device <b>22</b> in a horizontal direction can be reduced.

The image forming apparatus <b>1</b> performs image formation in the manner explained below. The formation of an image will be explained by taking the image creating device, which forms an image using a black toner, indicated by a reference character <b>21</b>K, as a typical example of the image creating devices. However, it should be noted that the following explanation is true of the other image creating devices.

At the time of image formation, the photoreceptor drum <b>25</b>K is rotation driven by a main motor (not shown). An AC (alternating current) bias (DC-(direct current) component being zero) is applied to the charging device <b>27</b>K to remove electricity, and the surface potential is set to a reference potential of about −50 V.

Next, the photoreceptor drum <b>25</b>K is uniformly charged at a potential substantially equal to a DC component by applying a DC bias with an AC bias superimposed thereon to the charging device <b>27</b>K, whereby the surface potential is charged to about −500 Volts to −700 Volts. It should be noted that a target charge potential is determined by a process control unit.

When the photoreceptor drum <b>25</b>K has been uniformly charged, a writing process is performed. An image as an object to be written is written with the writing device <b>29</b> according to digital image information delivered from a controller unit (not shown) to form an electrostatic latent image. That is, in the writing device <b>29</b>, a laser beam emitted from a laser light source based on a laser diode emission signal binarized for each color according to digital image information is applied through a cylindrical lens (not shown), a polygon motor <b>29</b>A, a fθ lens <b>29</b>B, a first mirror to a third mirror, and a WTL lens onto a corresponding one of the photoreceptor drums bearing respective color images, i.e., the photoreceptor drum <b>25</b>K in this case. The surface potential of the photoreceptor drum <b>25</b>K in its exposed areas becomes about −50 V, and an electrostatic latent image corresponding to the image information is created.

The electrostatic latent image formed on the photoreceptor drum <b>25</b>K is subjected to visible image processing with the developing device <b>26</b>K using a toner having a color complementary to a separated color. In the developing process, when DC: −300 Volts to −500 Volts with an AC bias superimposed thereon is applied to a developing sleeve, the toner (Q/M: −20 μC/g to −30 μC/g) is developed only in the image portion of which the potential is lowered by the writing light irradiation to form a toner image.

The toner image for each color subjected to the visible image processing by the developing process is transferred onto a recording sheet delivered at preset registration timing by the registration rollers <b>33</b>.

The toner images are electrostatically transferred from the respective photoreceptor drums onto the transfer belt <b>22</b>A by applying a bias having a reverse polarity to the toner by each of the transfer bias units <b>22</b>Y, <b>22</b>C, <b>22</b>M, and <b>22</b>K provided in the transfer device <b>22</b> at positions opposite to the photoreceptor drums <b>25</b>Y, <b>25</b>C, <b>25</b>M, and <b>25</b>K in the respective image creating devices. The superimposed and transferred toner images are simultaneously transferred by the secondary transfer bias unit <b>22</b>F onto the recording sheet.

The recording sheet subjected to transfer steps for respective colors is separated from the transfer belt <b>22</b>A by curvature separation with a drive-side roller (indicated by a reference character <b>22</b>A<b>1</b> in <figref idrefs="DRAWINGS">FIG. 1</figref> for convenience) in a transfer belt unit and is conveyed toward the fixing device <b>10</b>. In the fixing device <b>10</b>, when the recording sheet is passed through a fixing nip formed by a fixing belt and a pressure roller, the toner images are fixed onto the recording sheet. The recording sheet is then delivered to a catch tray <b>32</b>.

Image formation can be performed on one side of the recording sheet delivered after the fixation, as well as on both sides of the recording sheet. When image formation is to be performed on both sides of the recording sheet, the recording sheet after the fixation is conveyed to a reverse circulation path RP and is delivered toward the registration rollers <b>33</b> by a pair of delivery rollers RP<b>1</b> that is located at the end of the circulation path and also functions to deliver a sheet from the manual feed tray <b>23</b>. Switching between the recording sheet conveying path in the image formation on one side of the recording sheet and the recording sheet conveying path in the image formation on both sides of the recording sheet is performed by a conveying path switching pawl RP<b>2</b> provided in the rear of the fixing device <b>10</b>.

The image forming apparatus <b>1</b> includes a toner feed unit including toner feed bottles (hereinafter referred to as “toner bottles” for convenience) T<b>1</b>, T<b>2</b>, T<b>3</b>, and T<b>4</b>, which are toner containers containing respective color toners in order to newly feed toners to the developing devices that perform visible image processing for respective colors. The toner feed unit is provided through feed paths (not shown) in communication with the respective developing devices, such as developing device <b>26</b>K of image creating device <b>21</b>K.

The toner feed unit is characterized by a supporting structure for the toner bottles, and the characteristic configuration will be explained.

<figref idrefs="DRAWINGS">FIG. 2</figref> is an external view for explaining an installed state of a toner bottle (indicated by a reference character T<b>1</b> for convenience) in the toner feed unit. The toner bottle T<b>1</b> is mounted within a toner container storage space portion (hereinafter referred to as “storage space” for convenience) <b>100</b>A provided in a mounting member <b>100</b> constituting the toner feed unit.

The storage space <b>100</b>A is open at the top thereof and is configured so that the toner bottle T<b>1</b> can be inserted thereinto from a direction orthogonal to the longitudinal direction of the storage space <b>100</b>A, that is, can be inserted from above in <figref idrefs="DRAWINGS">FIG. 2</figref>.

A handle ring member <b>101</b> is mounted around the circumferential surface of one end in the longitudinal direction of the toner bottle T<b>1</b>. A gripper <b>101</b>A is provided, outside the handle ring member <b>101</b>, integrally with the handle ring member <b>101</b>. The gripper <b>101</b>A is gripped when the toner bottle T<b>1</b> is detached or attached from the image forming apparatus <b>1</b>.

A driven gear <b>102</b>, which engages with a drive gear provided in a drive source (not shown), is provided integrally with the end of the toner bottle T<b>1</b>.

Characteristic features of the present embodiment will be explained by taking a configuration comprising the toner feed unit provided on the upper part of the body casing as an object.

<figref idrefs="DRAWINGS">FIG. 3</figref> is a perspective view of a frame of the mounting member <b>100</b> of the toner feed unit. The frame is formed of a material different from the material constituting a body casing <b>200</b>. A curved surface formed of a concave portion, which is a shape into which the toner bottle is loaded, is formed at a position corresponding to the toner bottle storage space <b>100</b>A.

The mounting member (hereinafter referred to also as “frame” for convenience) <b>100</b> has side portions <b>100</b>A<b>1</b> of both sides in the longitudinal direction of the toner bottle loaded into the storage space <b>100</b>A and a rear portion <b>100</b>A<b>2</b> connecting the side portions <b>100</b>A<b>1</b>. The side portions <b>100</b>A<b>1</b> and the rear portion <b>100</b>A<b>2</b> have a flat surface and constitute a supporting surface of an image reading device <b>300</b> (see <figref idrefs="DRAWINGS">FIG. 4</figref>). Hereinafter, the supporting surface will be indicated by reference characters <b>100</b>A<b>1</b> and <b>100</b>A<b>2</b> for convenience.

The mounting member <b>100</b> includes legs <b>100</b>B at four corners of a surface opposite to the toner bottle mounting surface in the storage space <b>100</b>A. The legs <b>100</b>B extend downward in <figref idrefs="DRAWINGS">FIG. 3</figref>, that is, from the positions of the supporting surfaces <b>100</b>A<b>1</b>, <b>100</b>A<b>2</b> opposite to the image reading device <b>300</b> as the mounting object toward an installation surface (for example, a floor surface) of the body casing <b>200</b> as shown in <figref idrefs="DRAWINGS">FIG. 4</figref>.

The legs <b>100</b>B have a length defined by a distance from the positions of the supporting surfaces <b>100</b>A<b>1</b>, <b>100</b>A<b>2</b> to the installation surface. An elastic body <b>100</b>C (see <figref idrefs="DRAWINGS">FIG. 4</figref>) such as rubber is provided on the installation surface so that impact and load applied when the image reading device <b>300</b> is mounted can be absorbed by elastic deformation of the elastic body <b>100</b>C.

The legs <b>100</b>B are made of a sheet metal and are provided integrally with the supporting surfaces <b>100</b>A<b>1</b>, <b>100</b>A<b>2</b>. As shown in <figref idrefs="DRAWINGS">FIG. 4</figref>, when the image reading device <b>300</b> is loaded on the supporting surfaces <b>100</b>A<b>1</b>, <b>100</b>A<b>2</b>, the legs <b>100</b>B can withstand the weight of the image reading device <b>300</b>. In particular, the mounting member <b>100</b> has a vertically curved toner bottle mounting surface and thus it has a high rigidity in the vertical direction.

Thus, the weight load applied when the image reading device <b>300</b> is mounted acts directly on the mounting member <b>100</b>. The weight load can be supported by the structural shape of the mounting member <b>100</b> and does not act directly on the body casing <b>200</b> in which the mounting member <b>100</b> is incorporated. Consequently, the image reading device <b>300</b> can be supported while suppressing mechanical deformation of the body casing <b>200</b>.

When the image reading device <b>300</b> is mounted on the mounting member <b>100</b>, the image reading device <b>300</b> is supported by a three-point supporting structure using three supporting surfaces <b>100</b>A<b>1</b>, <b>100</b>A<b>2</b> provided on both side portions and a rear portion connecting the both side portions to each other. Accordingly, the image reading device <b>300</b> can be mounted in a stabile manner. Further, local load concentration in the mounting member <b>100</b> can be suppressed, and, by virtue of the configuration in cooperation with the sectional structure, the strength of the mounting member <b>100</b> per se can be maintained.

In particular, in the body casing <b>200</b> in which the mounting member <b>100</b> is incorporated, load applied to both side portions can be equalized by taking advantage of dispersion of the load to the supporting surfaces <b>100</b>A<b>1</b>, <b>100</b>A<b>2</b>. Thus, for example, twisting of the body casing caused when unequal load concentration has occurred on both side portions can be reliably prevented.

The built-in configuration of the mounting member <b>100</b> and the body casing <b>200</b> is as shown in <figref idrefs="DRAWINGS">FIGS. 5 and 6</figref>. That is, mounting holes <b>100</b>D, <b>200</b>A for fastening the mounting member <b>100</b> are provided on a part of opposed positions in the mounting member <b>100</b> and the body casing <b>200</b>. A cushioning material <b>400</b> is provided so as to cover the mounting hole <b>100</b>D.

Rubber or sponge and the like can be used as the cushioning material <b>400</b> and is applied to the body casing <b>200</b> side. The provision of the cushioning material <b>400</b> at the fastening position can cushion load and impact, caused in a mounted state, by elastic deformation, and the application of the load directly to the body casing <b>200</b> can be prevented.

Therefore, the application of load directly to the body casing <b>200</b> can be avoided. Further, by virtue of dispersion of load by the provision of the supporting surfaces <b>100</b>A<b>1</b>, <b>100</b>A<b>2</b>, twist deformation, which is likely to occur in the body casing, can be reliably prevented. Consequently, misregistration between image forming portions caused by such deformation can be prevented, and, thus, color shifting caused by the misregistration can be reliably prevented.

In particular, the mounting member <b>100</b> is not a member not related to the body casing <b>200</b> but is a member indispensable to the toner feed unit. Although the mounting member <b>100</b> is an existing structure, mere utilization of the structure can eliminate an adverse effect of an increase in load to the body casing without the need to change the structure of the body casing.

Next, another embodiment of the present invention will be explained. The characteristic feature of this embodiment lies in the positioning of an image reading device when the image reading device is mounted on the mounting member <b>100</b>.

<figref idrefs="DRAWINGS">FIG. 7</figref> is a diagram for explaining a configuration of the embodiment. As shown in <figref idrefs="DRAWINGS">FIG. 7</figref>, an upward protrusion <b>500</b> is provided on a part of each of the supporting surfaces <b>100</b>A<b>1</b>, <b>100</b>A<b>2</b> in the mounting member <b>100</b>. Particularly, as shown in <figref idrefs="DRAWINGS">FIG. 7</figref>, the upward protrusions <b>500</b> are provided on the upper surface on the supporting surface <b>100</b>A<b>1</b> side.

Positioning of the image reading device <b>300</b>, when the image reading device <b>300</b> is mounted, can be performed by fitting the protrusions <b>500</b> into fitting portions (not shown) provided on the side of the image reading device <b>300</b>. In particular, the protrusions <b>500</b> can be used as an indicator of position in mounting the image reading device <b>300</b> by afterward addition. Thus, the workability of mounting the image reading device <b>300</b> can be improved.

<figref idrefs="DRAWINGS">FIG. 8</figref> is a diagram for explaining a positioning structure when convex portions are provided on the image reading device <b>300</b> side. In <figref idrefs="DRAWINGS">FIG. 8</figref>, holes <b>100</b>F, into which protrusions provided on the bottom of the image reading device <b>300</b> side can be fitted, are provided on a part of the supporting surfaces <b>100</b>A<b>1</b>, <b>100</b>A<b>2</b> of the mounting member <b>100</b>. In this case, legs may be used as one of possible protrusions on the image reading device <b>300</b> side.

<figref idrefs="DRAWINGS">FIG. 9</figref> is a diagram for explaining a configuration that can realize a fine adjustment in positioning of the image reading device <b>300</b>. As shown in <figref idrefs="DRAWINGS">FIG. 9</figref>, long holes <b>100</b>A<b>3</b> having a longitudinal direction horizontal to a back and forth direction (a direction indicated by an arrow in the drawing) of the body casing <b>200</b> are provided in one supporting surface <b>100</b>A<b>1</b> on the top surface of the mounting member <b>100</b>. Reference holes <b>100</b>A<b>4</b>, which are round in shape, are provided on a top surface of the mounting member <b>100</b> corresponding to one side of the longitudinal direction of the long hole <b>100</b>A<b>3</b>, that is, a top surface of the mounting member <b>100</b> on the front side of the body casing <b>200</b> in <figref idrefs="DRAWINGS">FIG. 9</figref>.

The long holes <b>100</b>A<b>3</b> and the reference holes <b>100</b>A<b>4</b> are used for matching of mounting position in mounting the image reading device <b>300</b>. That is, the image reading device <b>300</b> can be mounted at a proper mounting position by fitting protrusions on the image reading device <b>300</b> side into the long holes <b>100</b>A<b>3</b> and performing sliding in the back and forth direction of the body casing <b>200</b> to fit other protrusion into the reference hole <b>100</b>A<b>4</b>.

The positioning structure is advantageous in that it can improve the workability of mounting the image reading device <b>300</b>. The same effect can also be attained by a configuration shown in <figref idrefs="DRAWINGS">FIG. 10</figref>.

<figref idrefs="DRAWINGS">FIG. 10</figref> is a diagram for explaining a configuration when the image reading device <b>300</b> is mounted, for example, by afterward addition.

An opening/closing unit <b>600</b>A is provided in an outer cover <b>600</b> provided so as to cover the body casing. The opening/closing unit <b>600</b>A is provided at positions corresponding to the positions at which the positioning structure shown in <figref idrefs="DRAWINGS">FIG. 7</figref> or <b>8</b> is provided.

For example, the opening/closing unit <b>600</b>A is formed of a portion that has been subjected to perforation or the like. Upon depression of the portion, the opening/closing unit <b>600</b>A is opened. Alternatively, the opening/closing unit <b>600</b>A may be formed of a color display portion. When the opening/closing unit <b>600</b>A is opened, the positioning unit is externally exposed. Consequently, the position at which the image reading device <b>300</b> is mounted can easily be determined.

According to the present invention, while ensuring the rigidity provided by the shape and structure of the toner feed unit, deformation of the body casing caused by the application of a load of the mounted device to the body casing as a result of direct application of the load of the mounted device can be prevented.

Furthermore, while ensuring the stability of the mounted device, a load applied from the mounted device can be dispersed, whereby deformation, which is likely to occur in the toner feed unit by load concentration, can also be prevented. Thus, the prevention of deformation of the body casing and the prevention of defective-image formation caused by the deformation of the body casing can be realized without the need to specially change the structure of the body casing as an existing structure.

Furthermore, according to the present invention, direct application of the load to the body casing can be prevented more reliably.

Furthermore, according to the present invention, an elastic body such as rubber or a cushioning material is used so that the load from the mounted device can be cushioned. Therefore, load concentration on the body casing can be prevented.

Additionally, according to the present invention, positioning of mounting position of the device to be mounted can easily be performed, and, thus, the workability of mounting can be improved.

Although the invention has been described with respect to specific embodiments for a complete and clear disclosure, the appended claims are not to be thus limited but are to be construed as embodying all modifications and alternative constructions that may occur to one skilled in the art that fairly fall within the basic teaching herein set forth.